The invention relates to spring coil assemblies, and more particularly to systems for making spring coil assemblies.
Spring coil assemblies are well known for use in mattresses, furniture, cushions and the like. In the case of mattresses, it is known to use two types of coils in constructing the spring coil assembly. The industry commonly designates these two types of coils as right-hand coils and left-hand coils based on the location and orientation of the end wind of the coil. As used herein and in the appended claims, the terms xe2x80x9cright-hand coilsxe2x80x9d and xe2x80x9cleft-hand coilsxe2x80x9d are used only by way of example, and different terminology could be substituted.
FIG. 1 shows a typical prior art coil assembly 10. The prior art coil assembly includes a plurality of substantially identical adjacent rows R1, R2, R3 . . . Each row R consists of alternating right-hand (designated both in FIG. 1 and in the other drawings as RH) and left-hand (designated as LH) coils. The plurality of adjacent rows forms a plurality of adjacent columns C1, C2, C3 . . . . Each column C consists entirely of all right-hand coils or all left-hand coils. To remain competitive, manufacturers mass produce the spring coil assemblies, and are therefore limited to coil configurations obtainable with automated assembly machines. Consequently, known spring coil assemblies comprised of left-hand and right-hand coils have been configured substantially as shown in FIG. 1.
To vary the overall firmness of the assembly, it is known to utilize coils made from different gauges of wire, thereby varying the spring characteristics and making the coil assembly softer or firmer. Again, due to the limitations of mass production, all of the right-hand coils are made from the same gauge of wire and all of the left-hand coils are made from the same gauge of wire. While the gauge of wire used for the left-hand coils may be different from the gauge of wire used for the right-hand coils, there are at most only two gauges of wire used in any one spring coil assembly. Since the configuration of coils maintains substantially the same pattern seen in FIG. 1, varying the wire gauge only allows for substantially homogenous variation of the firmness over the entire assembly.
In order to vary the firmness in different areas of the assembly, it is necessary to vary the spacing between the coils in each row. Due to the automated equipment used for mass production, this varied spacing is consistent throughout the rows of the spring coil assembly. This means that softer areas and firmer areas will run across the entire spring assembly in bands, i.e., along columns of coils.
The present invention provides a mattress or spring coil assembly construction having variation along the rows of the spring assembly to suit the needs of the consumer. The arrangement of coils is flexible, however, in that variations or permutations of the coil arrangement can be achieved within the scope of the present invention to provide multiple embodiments of the spring coil assembly. The multiple embodiments provide various characteristics and can be used to change the firmness of mass-produced coil assemblies in predetermined locations or zones as well as over the entire assembly. Advantageously, this coil assembly customization moves beyond simple selection of the firmness of the entire spring coil assembly or selected bands, and now allows the consumer to specify zones of the assembly where softer or firmer support is desired. The zones need not run across the entire assembly and therefore allow softer areas to be completely surrounded by firmer areas or vice-versa.
The present invention also provides an apparatus for making and assembling the multiple spring coil assembly embodiments. In one embodiment, the apparatus comprises a main conveyor adapted to convey a plurality of coils along an axis, an assembler which is operable to intertwine a plurality of coils into a spring coil assembly, and a transfer station operable to move a plurality of coils from the main conveyor into the assembler. The transfer station includes a plurality of pusher arms, each of which have a gripper that is operable to grasp an individual coil. The transfer station also includes a carriage supporting the gripper arms and a device for shifting the carriage in a direction substantially parallel to the axis so that the plurality of coils carried by the gripper arms are displaced in the direction of travel of the conveyor.
In another embodiment, the apparatus includes a coil forming machine having a wire feed advancing mechanism and being capable of forming coils in response to the advancement of wire by the wire feed advancing mechanism. The apparatus also includes a programmable control system capable of selectively varying the advancement of wire by the wire feed advancing mechanism between a consistent advancement, wherein coils are formed and placed on a main conveyor in predetermined consistent intervals, and an inconsistent advancement, wherein coils are formed and placed on the main conveyor in predetermined inconsistent intervals. In one aspect of the invention, the apparatus also includes a sensor element capable of producing a signal that can be selectively interpreted by the control system to stop the manufacturing of the spring coil assembly when the spacing of the coils on the main conveyor is inconsistent, or to permit the manufacturing of the spring coil assembly when the spacing of the coils on the main conveyor is inconsistent.
The present invention further provides a method of arranging coils in a spring coil assembly. The method includes arranging a first plurality of right-hand coils in spaced apart relation in a first row, arranging a first plurality of left-hand coils in spaced apart relation in the first row such that each of the first plurality of left-hand coils in the first row is located between a respective pair of right-hand coils in the first row, arranging a second plurality of right-hand coils in spaced apart relation in a second row, arranging a second plurality of left-hand coils in spaced apart relation in the second row such that each of the second plurality of left-hand coils in the second row is located between a respective pair of right-hand coils in the second row, and arranging the first and second rows such that the first plurality of right-hand coils in the first row is out of phase with the second plurality of right-hand coils in the second row.
In another embodiment, the method includes providing a coil forming machine having a wire feed advancing mechanism and that is capable of forming coils in response to the advancement of wire by the wire feed advancing mechanism. The method further includes selectively varying the advancement of wire by the wire feed advancing mechanism between a consistent advancement, wherein coils are formed and placed on a main conveyor in predetermined consistent intervals, and an inconsistent advancement, wherein coils are formed and placed on the main conveyor in predetermined inconsistent intervals. In one aspect of the invention, the method also includes selectively disregarding or disabling a sensor element that produces a signal intended to stop the manufacturing of the spring coil assembly when the coils on the main conveyor are spaced at inconsistent intervals.
Other features and advantages of the invention will become apparent to those skilled in the art upon review of the following detailed description, claims, and drawings.